With the continued progress of globalization, more corporations than ever before have workgroups spread across countries and continents across the world. To support and increase the productivity of remote and telecommuting workgroups, communications companies are considering more cost effective network services and solutions that combine voice, wireless, data and video functionality. Acquiring these desired network services and solutions requires connections from the Internet and wireless and wireline networks to Public Switched Telephone Networks (PSTNs) using a flexible, robust, scalable and cost-effective media gateway.
Today, all communications can be routed through computers. Widespread access to broadband Internet and the ubiquity of Internet Protocol (IP) enable the convergence of voice, data and video. Media gateways provide the ability to switch voice media between a network and its access point. Using Digital Subscriber Line (DSL) and fast-Internet cable technology, a media gateway converts, compresses, and packetizes voice data for transmission back-and-forth across the Internet backbone for wireline and wireless phones. Media gateways sit at the intersection of the PSTNs and wireless or IP-based networks.
Multiple market demands are pushing companies to converge all of their media services using media gateways with VoIP capabilities. As such, the development of media servers has allowed this convergence of media services into media gateways with VoIP capabilities. A media server is responsible for sending a continuous stream of data representing audio, video or other media in real-time. Often times, high-availability for these systems are desired. To obtain high-availability more than one server is run, with one of them operating as the master (serving the clients directly) and the others operating in standby mode (called “backup nodes”). If the master fails, a new master is selected from the backup nodes to serve clients. This switch from old master to new master is called fail-over. Transparent fail-over is when the clients do not notice the switch between servers.
In order to achieve transparent failover, the backup nodes must be aware of what the master is sending at any time. This typically requires all requests to be executed on all nodes simultaneously and the state of the master to be replicated to the other nodes so that they are ready to take over the master at any time. Usually, this is achieved via a standard technique to synchronize all of the servers by replicating the current buffer/segment of the data that is being sent through all of the back-up nodes. This synchronization is done many times every second. Unfortunately, executing all requests on all nodes is a time and resource consuming process for the media server. Therefore, a mechanism to provide time and resource efficient transparent fail-over for media server nodes would be beneficial.